Steering mechanism for vessels



Feb. 13, 1945. J". H. HAMMOND, JR 2,369,456

STEERING MECHANISM FOR VESSELS 4 I Filed March 18, 1942 l' 4 sheets-sheet 1 N NIU INVENTOR y JOHN HAYs-HAMM0ND,JR. EI I y' my l o n l v4 Feb. 13, 1945. J, H. HAMMOND, JR 2,369,456

STEERING MECHANISM FOR VESSELS Filed March 18, 1942 4 Sheets-Sheet 2 E 7g REPEAT R y REPEATER 2'9 MOTO-R MOTOR INVENTOR 3dorm HAvs HMMoND, JR. El: E i 3%( NEY J. H. HAMMOND, JR 2,369,456

STEERING MECHANISM FOR VESSELS Feb. 13, 1945.

4 Sheets-Sheet 3 `FIled. March 18, 1942 IBI 1 INVENToR JOHN HAYs HAMMoND, JR..

Laan

NEY

IIE llIIt huslllm Feb. 13, 1945.

.STEERING MECHANISM FOR VESSELS Filed March 18, 1942 4 Sheets-Sheet 4 INVENTOR J OHN HAvs VHAMMo No, JR.

NEY

i place;

` Patented Feb.` 1945 y y p "2,369,453` p STEERING MECHIANISM FoRvEssELs y John Hays Hammond, Jr.,` Gluucester,"Mass`.l l Application Marchis, islayserial No. lisait?` y solaires. y(c1. iis-sn This invention relates to variable pitch propellers andhas foran" object to providemechanism forV automatically varying the pitches of a plurality of propellers in accordance With'the operation of the steering means.` i l The invention 4provides means in connection with the steering mechanism of the vessel to cause the pitches `of a plurality of` propellersto vary in such a manner as to assist in thesteering of the vessel. i i

More specifically the invention` provides means to control the pitches of` the propellers `of a twin screw vessel so that when the vessel is steered to port the pitch of the port propeller will bedecreased and the `pitch of thestarboard propeller increased andl `when the vessel is steered to starboard the :reverse action Will take In this manner the manoeuvering of the vessel is greatly facilitated and the steering accel` erated. If desired, the steering maybe accomplished entirely by varying the pitch of the propellers `witho-utthe use of the rudder. Means are also provided for varying the relationship `between the steering `mechanismand `the pitch i changing devices.

The invention alsoprovides means for`allow;

`ing the rudderto `be `moved thru a predeter-` mined adjustable angle eitherto port or stari board before the propeller pitch changing mech:`

anism comes into action,` Means vare `also provided for rapidlybhanging the propeller pitch control mechanism from automatic `to manual or vice versa. i

The invention alsoconsists in certain new and original. features of construction and combina-1 tions of parts hereinafterset forth and claimed,

Although the novel features which are believed to be characteristic of this invention will -be particularly pointed out in the claims ap pended hereto, the invention itself., `as to its ob- Iiects andadvantages, the mode of i its operation and the manner of its organization may be bet-` ter understood by referring to the Vfollowing description taken in connection with theaccompanyingdrawings forming a `part thereof, in which; l l v p Figure l illustrates diagrammatically the system y for `controlling the propeller pitches, by ,means 'of the` steering mechanism of the vessel,

\ Figure 2 isalfront elevationpartly1 in section of the control apparatus;` y u y y `FiguzreA is a transverse section of the control apparatus taken on line 3 1-3 of Figure 2,. m

iary propeller control.

Figure 4 is afragmentary section taken on line l-oflFigure 3, l l

Figure 5 is an end elevation of the upper part ofthe control apparatus', andl l y Figure 6" illustrates diagrammatically the c courseof a vessel with and without the auxil- `Like reference characters denote like parts in the several figures of the drawings. i l i 'lin thefollowing description and in the claims parts will be identified `by `speciilcnarnes` for convenience, but they;V are intended to be as generic'in` their application to` similar parts as the art willperrnit; .i i

`In accordance withthe present invention, the' port and starboard propellers are providedwith pitch changing mechanisms having a follow up indicator `and are connected for individual manual setting bycontrol` handles mounted on a standard near the steering wheel. Provision is `made for disconnecting thecontrol by themanual control handles and connecting the` pitch changing mechanisms for" automatic operation by an element actuated with therudder so that in. making a turn, thepitch of the outer propel- 1er is increased and the pitch ofthe inner propeller is decreased. 'Suitable linkage are provided for Varying the ratio of the rudder move- `ment to that of the pitch changing mechanism. `An adjustable lost motion device permits a lim-A ited movement of the rudder as desired Without bringing the pitch changing mechanism into op- `eration. Suitable clutches permit the steering l control mechanismto be operatively disconnect pellers IZP and IZSrespectively, variable pitch,

ed from the rudder and connected only tothe pitch changing mechanism so that steering can beeiected by thepropellers alone. i

y Referring to the accompanying drawings, and more particularly to` Figure 1, a diagrammatic layout of the propeller control mechanism is shown which includes a `rudder l0, a rudder control I|, port and starboard variable pitch promechanisrnsilSP and 3S for varyingthe pitch of the propellers [2P and I2S respectively, two

governor controlled prime movers MP and MS for driving the propellers I2P and I 2S, a hand c steering wheel l5 for `manually operating the rudder'v I (l, gyro pilot 16 for steering thevessel automatically and a control mechanism l1 for varying the pitch of the propellers |2P'and 12S in accordance with the throwof therudder I 0.

The gyro pilot ts is proviciedwith a hans wheel' p IB. n

The propellers l IZP and 12S are provided with adjustable blades 20 and are Lattached to hollow shafts 2| which are connected to the variable pitch mechanisms i3P and |3S, which may be off any well known and standard construction such as thatl manufactured by the S. Morgan Smith Company, of York, Pennsylvania, the details of which form no partof the present invention and are accordingly not specifically set forth herein, The mechanism in general comprises a rod 22 slidable longitudinally within the shaft 2| and connectedto control the pitch of the blades 20. The rod 22 is prevented from rotating with respect to the shaft 2|v by means ofv a key 23 which slides in a keyway 2.5 cut in the shaft 2|. The inner end of the shaft 22 is attached to a nut 26 which is provided with internal threads 21. member 28 which is attached to the slow speed shaft 29 of a reduction gearing 30. The high speed shaft 3| of this gearing is driven by a motor 32.' l

The motor 32 is also 'connected to the high speed shaft 33 'of a reduction gearing 35, the low speed shaft 36 o'f which is connected to Selsyn repeating motor 31. All of'this mechanism is mounted in the casing 38'which forms part of the drive shaft 2|.

Secured to a bracket 39 of insulating material are three brushes 40, 4| and 42 Awhich engage three slip rings 43,44 and 45, which are mountedron but insulated from-the casing 38. The slip rings 43 and 45 are connected to the revers.- ing windings of the motor 32 and the slip ring 4'4 is connected to the return lead fromwthese windings. The brushes 40, 4| 'and 42 are connected toV reversingrelays 41B and 41S;

Secured to the bracket 39 areve brushes 48-52 which engage ve slip rings 53-51 which are mounted on but insulated from 'the casing 38. The slip rings 53--51 are connected to the Selsyn motor 31. vThe brushes 48-52 areconnected to control boxes 58P and 58S.

`The rudder l is provided with the usual rudder quadrant 60 which is connected by means of cables 6| and 62 to acable drum 63. The drum 63 is attached to a gear 65 which meshes with a pinion 66 which is mounted on a shaft 61. The shaft 61 is connected thru a clutch 63 to a bevel pinion 69 which meshes with a bevel gear 10. Meshing with the bevel gear are three other bevel pinions 1I, 12 and 13. connected thru a clutch 'and bevel gears l16 to the hand steering wheel I5 and the pinion 12 is connected thru a clutch 11 and bevel gears 18 to the gyro pilot I6.

The pinion 13 is connected to a shaft 80 which is rotatably mounted in brackets 8| and 82 (Figures 2 and 3) in the control mechanism I1 and is provided with a keyway 83. Slidably mounted on the shaft 80 is a worm 85 which is provided with a key (not shown) which slides in the keyway 83 which causes the worm 85 to rotate with theshaft 00. Attached to the upper end of the shaft is a bevel pinion 86 which meshes with a bevel gear 81. The gear B1 is attached to a shaft 88 to the outer end of which is secured a pointer 8 9 which registers with a scale 90 (Figure 1) mounted onthe front of the case of the control mechanism I1 and'which is graduated in degrees of rudder angle.

Slidably mounted on the shaft 80 are two mem; bers 9| and 92 which are also slidablyrnounted on two rods 93 and 94 and which are threaded on a shaft 95, the member 3| having a right hand thread and vthe member'92'havng a' left -hand thread. Secured to ther upper end of the shaft 95 is a bevel pinion 96 which meshes with a bevel gear 91 secured to a shaft 98. Mounted on the shaft 98 is a knurled knob 99 and a pointer |00 which registers with a scale |0| (Figure l) mounted on the front of the case of the control mechanism I1.

Meshing with the worm 85 is a worm wheel |65 which is secured to a shaft |06 which has a bearing in an arm |01 of the bracket 8|. Secured to the shaft |00 is an arm |08 to one end of which is attached a counter-weight |09 and to the other end a pin |03 to which is pivotallyconnected the lower end of a link I I0. Mounted on Threaded into the nut 26 is a V The pinion 1I is.

the frame |31.

the bracket si isa T-shaped block m to which is secured two flat springs ||2 and |3. Secured to the worm wheel |05 is a pin ||ii which is nor- 'mally positioned between the two springs |12 and Secured to the link ||0 is a pin ||6 which slides in a slot ||1 provided in the head of a T-shaped member IIB. The member I ISs slidably mounted in a bracket |9 and is provided with athreaded bore which is engaged by the threaded end of a rod |20. The rod |20 is provided with a V-shaped groove |2| (Figure 2) which is engaged by a set screw |22. This prevents longitudinal motion of therod |20 but allowsit to..be freely rotated. Secured to the rod |20 is a knurled knob |23 and a pointer |25 which registers with a scale |26 (Figure l) mounted on the front of the case of the control mechanism |1.- I Y -Secured to the upper end of the link ||0 is a pin |30 which slides in a slot I3! provided in an arm |32 which is rotatably mounted on two shafts |33 and |34 (Figures 2 and 4) which are journaled in two brackets |35 and |36 (Figure 2) mounted on a cross frame |31. Mounted on but insulated from the arm |32 is a segment |33- of conducting material (Figure 4) which is engaged by a brush |39 which is mounted onY but insulated from the frame |31. Secured to the segment |38 are two-brushes |40 and |4!. The brush |40 cooperates with two semi-circular conducting segments |42 and |43 which are mount-- ed on one yside of a circular drumk |45of insulating material which is secured to the shaft |33. The segments |42 and |43 are electrically connected to two slip rings |46 and |41respectively mounted on the periphery of the drum I 45. Engaging the slip rings |46 and |41 are two brushes |43 and |49 which arek mounted on but insulated from the frame |31.

The brush 4I cooperates with two semi-circular conducting segments which are mounted on one side of a circular drum |52which is secured to the shaft |34, and are electrically connected to two slip rings |53 and |54 mounted on the periphery of the drum |52. The slip rings |53 and |54 are engaged byvtwo brushes |55 and |56 which are mounted on but insulated from Slidably mounted on the shaft |33 is a collar 51 which is provided with akey |58 which slides in a'keyway |59 provided in the shaft |33, so that the collarv |51 may slide longitudinally. on the shaft |33 but cannot rotate with respect thereto. The collar |51 is provided with a groove |60 which is engaged by a piny (not shown) carried on the endof an arm |6|. The arm |6| is secured to the, lower end of the shaft |62 which has a bearing in an extension of the bracket |35. Secured to the upper end of theshaft |62 is a segment of a worm gear-.|63 which engages aworm |65.,secured to .a

" The clutch 11 is then opened and the rudder is brought to a central position by turning the hand steering wheel l in the usual manner. The mechanism will now be in the neutral position as shown in Figure 3. The knobs |68 and 2|| are turned so that the pointers |69 and 2|2 indicate the, normal pitch angles which have been set on the port and starboard propellers. By turning the knob |68 the worm |65 will be rotated, which in turn will rotate the worm wheel |63. This motion will be transmitted by means of the shaft |62 and arm |6| to the collar |51 which will be moved to the right and at the same time rotated thru a small angle, as the pin |13 slides in the diagonalslot |12. The rotation of the collar |51 will be transmitted to the shaft |33 by means of the key |58. As the shaft |33 rotates it will rotate the drum |45. When the pointer |69 indicates the pitch angle to which pointerv |96has been set as above described, the y ner cause a small rotation of the shaft |34. As

the shaft |34 rotates it will rotate the drum' |52. When the setting of the pointer 2|2 corresponds to that of' pointer 235 the insulation betweenl the semi-circular segments will be under the brush 4|.

For varying the ratio of the change of propeller pitch to the rudder throw, the knob |23 is turned until the pointer |25 registers the desired ratio on the dial |26. Thus for example, if it is desired to have a high ratio of propeller pitch to rudder angle the kn`ob |23 is turned to the right, which will cause-the threaded shaft to be rotated in a clockwise direction-thus entering the member ||8 which will be moved to the left, as the shaft |20 is restrained from longitudinal movement bythe set screw |22. As the member ||8 moves to the left the link I0v will be rotated by means of the pin ||6 thru a small angle in a counterclockwise direction about the pin |03. The pin |30 will slide to the left in the slot |3| so that the lever arm from the shaft |34 to the pin |30 will be less than the lever arm from the shaft |06 to the pin |03, thus increasing the In order to vary the angle thru which the rudder may be turned before affectingthe pitch of the propellers the knob 99 may be manipulated until the pointer |00 registers the desired 'rudder throw on the dial |0l. Thus if it is desired to increase this angle the knob 99 is turned clockwise which by means of the bevel gear 91 and bevel pinion 96, will cause the shaft 95 to be rotated in a clockwise direction, as seen from above.

This rotation will cause the two members 9| and v92 to move apart, due to the right and `left threads cut on the shaft 95, which will permit the worm 85 to slide a greater distancer along the shaft 80 before it engages these members. If it is desired to decrease the angle the knob 99 As shown in Figure 3 the mechanism is set for a mean ratio.

is turned counterclockwise which causes 'the members 9| and 92 to move closer together.

f When it is desired to have the pitch changing mechanism function in |conjunction with the rudder the handle 241 is moved to the left into the position.shown in Figure 2, thus throwing the switches 231 and 240 to the right and left respectively, which connects the brushes |48 and |49 to the reversing relay 41P and the brushes |55 and |56 to the 4reversing relay 41S.

' The 4vessel is now steered in the usual manner by means of the steering wheel I5, which acting thru the bevelgears 16,\1|, 10 and 69, rotates the pinion 66, which by means of the gear rotates the drum 63. The rotation of the drum 63, acting thru the cables 6| and 62, turns the rudder |0 in a well known manner.

During the operation the bevel gear 13 will be rotated which will, by means of the shaft 80, rotate the worm 85. As the gear |05 is held in a central position by means of the springs ||2 and I3 the worm 85 will merely slide along the shaft 80 until it comes up against one or the other of the members 9| or 92 depending on whether vthe rudder is turned to the port or starboard.

members 9| and 92, which, as already described,

is set by rotating the knob 99. In Figure 2 the members 9| and 92 are shown in a mean position, which, 'for example, may allow the rudder I0 to be moved'thru an angle of five degrees on either side of the central position without aiecting the gear |05. i

If the rudder l0 is turned more than five de grees, say to port, the worm 85 will slide up along the shaft B0, when it is turned, until it engages the member 9|, which will prevent any further longitudinal movement of the worm 85. When the shaft 80 is rotated further the worm 85 will cause the gear |05 to start rotating in a counterclockwise direction, as seen in Figure 3; This motion, acting thru`the lever |08, will cause the link 0 to be moved upward, which will by means of the pin |30 cause the arm |32, segment |38 and brushes |40 and |4| to be rotated in a counterclockwise direction.

The brush |40 will `then engage the segment |43 which will close a circuit from the battery '246, switch 245, conductor 243, brush |39, segment |38, brush |40, segment |43, slip ring |41, brush 49, switch 231, conductor 239, reversing relay 41P back to the battery 246. This will operate the reversing relay 41P which will supply current from the source 249 to the motor 32, the rotation of which will be vtransmitted thru the reduction gearing 30 to the member 28 which will be rotated in such a direction as to cause it to move out of the nut 26. As the member 28 is held fixed longitudinally this will cause the nut 26v and shaft 22 to be moved downward to decrease the pitch of the blades 20 of the port propeller |2P. y f

At the same time that the motor 32 rotates the member 28 it will, by means of the reduction gearing 35, rotate the Selsyn motor 31 thru a fraction of a revolution. This motion will be repeated to theSelsyn motor |19, which by means of the bevel gears ITT-|18, will transmit the rotation to the drum |45 which will be rotated until the insulation between the segments |42 and |43 is under the brush |40 at which time the relay 41P will be operated to stop the motor 32.

At the same timethe brush |4I will engage the lower semi-circular segment `onuthe side the drum |52, which in a manner similar to that just i described willenergize the reversingrelaylls.

As this relay is `wired up in an opposite manner to thatof the relayllP,V itwill operate to supply current from the source 269 to the motor `32' so as to cause the member 2 8 to move into the hut 26, which together with the shaft 22 will beinoved upward to increase the pitch of the blades '2li yof the starboard propeller I2S. Thismotion is re-4 'portional to the angle thru which the rudder IU is turned in addition `tothe angle set on the dial- IUI. In this way,the turning `moment "to port ci the vessel is augmented by the vactlonof the propellers, as the thrust of the port propeller I`2P `is decreased due to the decrease of pitch andthe thrust of the starboard propeller IZS is increased dueto the increase or pitch.` I i AFigure 6 shows in a general Way the actionhof l the pitch changing mechanism on the turning radius of the vessel. The curve 25| indicates the course or the vessel when it is steered` to port with the control handle 241 thrown `to tlreiright, so that the propeller pitch changing mechanism is inoperative and curve `2`52`shows the course of the vessel when it is steered to port, lloldingthe "same rudder angle, but with thecontrol handle `2Il'l` thrown to `the left, so that the( propeller pitch changing mechanism is operative. i It is "seen `fromthese two `curves thatthe vessel can be manoeuvered much more rapidly with the use of the propellerpitch changing mechanism in addition "to the conventional action ofthe rudder.

"When the vessel is steeredto starboardthe reverse action takes place and the pitch of the t starboard propeller |2s is decreased and the pitch of the port propeller [2P is increased, this change of pitch being proportional to theangle thru which the rudder I is turned in addition to the angle indicated on the dial IUI the courses `followed by the vessel when it is steered to starf board without and with the propeller pitch control are indicated `by the curves 253 and `254 regspectiyely. v j As already stated the angle thru which th `rudder may be turned without bringing into `aotion the propeller pitch changing mechanism can be Varied by turning the knob 9'9. If desired this angle may be `decreased tozero by bringing the two members 9| `and 92 into engagement with the worm 85. lUnder these conditions the pro-l peller'pitch changing mechanism will become op-` erative as soon asthe rudder I0 is turned from its central position.`

I The rate at whicllthe propeller pitch-changes` in relation to the rudder'throw may be varied `by turning the knob |23. If' this knob is turned 'in' i a` clockwise direction so as to cause the member I I8 to befmoved to the left, as seen in' Figure 3, the lever arm from the shaft |34 to the pin |30 Will be decreased, so lthat tl'le` Contacts H0 arid' "IM will be moyed'thru a greater angle for a given rudder throw/*thus increasing the change* of the pitch of the Propellers wllichin turn"` will iii-- crease the:` turning moment of the vessel causing e it to turn with a" shorter' radius asfindicated `by the curveszss and''oi Figure o; ly turning `the knob l2-3 in a ocunter`elockwise direction "the opposite effect iS produced and the vessel will Itorri with a `greater radius as indicated by 'the curves'251 and 258. Y

If Ait is desired to use the gylo pilot I6 the rudder I0 isbro'ughtto a central positioiibymeans :er the steering wheel is andthe clutch it is disengaged. The fhand wheel I8 oi the gyro pilot islbro'ught to a central position and the clutch il is engaged; The vessel is then steered by inai nipnlating the hand wheel la of the gyro pilot I es" is turned ihaicounterecloclswise direction-ias i `ltin a well known manner that need not be more `fully described herein. The steeringl motion is transmitted to theshaft 18u which operates to :vary .thepropeller n ehesas' already described riso desired the vessel may be steered entirely;r bythe Iactionioi the `propellers without the use therudder l0. in case the rudder In is set y in a central position by means of the steering wheel and the clutch 68 is opened.. The knob far as possible thus bringing the members 9| and 92 into engagement with the `ritorno tlsa The knob 123 is turned in a clockwise direction `as rarr as possible, thus giving the maximum `action of the propeller pitchchanging mechanism.

`Under these conditions when the .steering wheel I5 isturned theshaft will be rotated thus roland cannotbezchangelrorn the bridge,

toting the-worin c5 the vaction or which will be immediately transmittedby the gear W5 and link I||u to the brushes |46 and 4|5 which will, as already described,` operate the pitch changing mechanisms |3P1faiid 1|3s `at a maximum rate. This will causen a turning moment to be' produced `which will steerftl'le vessel topo'rit `or starboard 4as desired. `Itisthus seenthatin case the rudby the use ofthe propellerpitch changing 'mecha anism alone. t i

Ii it is` desired to put `the automatic pitch changing mechanism out ci operation the handle `241isthrown to the rlghttlius throwing the switchgztl tothe left and the switch 24u to the l right. `This willrijjnalie the brushes |40 and |4| inoperative and the brushes we and `2lb opera;

tive. 'lhe blades zufot the port and. starboard pr'opellers I zPandz 1| 2s `will: then be v brought back to their normal pitchangles, as indicated by the poiiittersws and 235,.` this action taking place in e, manner similar to that already' described connection with vthe manual setting of pro lbeller pitches, The pitches of. the propel-1ers |21#` and |25 may `now be changed as Ydesiredfby ma nipulating the handles and 233 as already descrilcfed.;` Under' these conditlonssteoring will bouche-entirely by the action of the rudder lll. 4ritter:the propellers |12P` and |253 have been set vat the desired:pitch the switch: 245 may be openedr thusputting the pitch changing mecha nismlsoompletely out of operation. The proe pellets will then :act aspropellers of xed pitch Aitnoughonly a'iew or the various `iornfis wliichthis invention may be einbodiedhave been shownherein, it is to be `understood that the itivolition iis-not limited to any specic construction but might be embodied in various forms without' departing `from the spirit or the invention: or the scopeofltheappendedclaims;

"'W'httisclaiined is! i l. A steering system for vessels ing pitchohangihg mechanisms connected re-V spectivelyftolehange the-pitch diede-n. or said `hai/ing port I `arid-Istarlcoardvariable pitch propellers', compris- ,control mechanism connected to actuate said joint actuating means, and means selectively connecting said individual actuating means or said joint actuating means to operate said pitch changing mechanisms. I

2. Afsteering system for vessels having port and starboard variable pitch propellers, comprising pitch changing mechanisms connected respectively to change the pitch of each of said propellers, individual actuating means for independently actuating eachof said pitch changing mechanisms, manual control means for said individual actuating means for setting said pitch to a pre-determined value, jointactuating means for simultaneously actuating both of said pitch changing mechanisms in opposite sense to increase the pitch of one of said propellers and to decrease the pitch of the` other of said propel- 1ers, steering control mechanism connected to actuate said joint actuating means automatically for steering said vessel by said propellers, and means selectively connecting said individual actuating means or said joint actuating means to operate said pitch changing mechanisms.

3. A steering system for vessels having port and starboard variable pitch propellers, comprising pitch changing mechanisms connected respectively to change the pitch of each of s'aid propellers, individual pitch indicating means to indicate the pitch 4setting of each propeller, re-

peater mechanisms actuated respectively by each of said pitch changing mechanisms and connected to actuate said pitch indicating means,

individual actuating means for independently actuating each of said pitch changing mechanisms, manual control means for said individual actuating means for setting said pitch to a predetermined value, joint actuating means for simultaneously actuating both of said pitch changingA mechanisms in opposite sense to increase the pitch of one of said propellers and to decrease the pitch of the other of said propellers, steering control mechanism connected to actuate said joint actuating means automatically for steering sai-d vessel by said propellers, and means selectively connecting said individual actuating means or said joint actuating means to operate said pitch changing mechanisms.

4. A steering system for vessels having port and starboard variable pitch propellers, comprising pitch changing mechanisms connected respectively to change the pitch of each of said propellers, control circuits including reversing contacts connected to actuate said pitch changing mechanisms, rotatable drums carrying said.v contacts, a brush selectively engaging the con-I 'and follow-up mechanism including repeaters actuated by said pitch changing mechanisms to cause corresponding rotation of said drums for n breaking said circuits when said pitch has been changed to the desired value.

5. A steering system for vvessels having port and starboard variable pitch propellers, compris- V ing pitch changing mechanisms connected respectively to change the pitch of each of said propellers, control circuits including reversing contacts connected to actuate said pitch changing mechanisms, rotatable drums carrying said contacts, a brush selectively engaging the contacts on each drum, a control arm carrying said brushes, steering control mechanism connected to shift said arm for selectively closing said contacts in accordance with steering requirements, and manual means to adjust independently the setting of/each drum with respect to its brush for varying the pitch response characteristics of said propellers.

6. A steering Vsystem rfor vessels having port .and starboard variable pitch propellers, comprising pitch changing mechanisms connected respectively to change the pitch of each of said propellers, control circuits connected to actuate said pitch changing mechanisms, and manual y and automatic control meansfor said circuits .comprising a. pair of rotatable drums for each of said circuits, reversing contacts for said circuits carried Vby each of said drums, brushes selectively engaging the contacts of each drum, steering control means connected to shift one of said brushes [for selectively closing said contacts in accordance with steering requirements, manual `means connected to shift the other of said brushes, switch means selectively connecting the contacts of one or the other of said drums to said circuits, follow-up mechanism including repeaters actuated by each of said pitch changing mechanisms to cause corresponding rotation of both of said drums for breaking said circuits When said pitch has been changed to the desired value, and adjusting mechanism to adjust the relative positions olf said drums forvarying the pitch response characteristics of said propellers.

'7. A steering system for vessels' having a steering rudder and port `and starboard variable pitch propellers, comprising pitch changing mechanisms connected respectively to change the pitch of each of said propellers, pitch actuating means for simultaneously actuating both of said pitch changing mechanisms in opposite sense to increase the pitch of one of said propellers and to Adecrease the pitch of the other of said propellers, steering control mechanism connected to actuate said rudder and said pitch-actuation means Vfor automatically varying the pitch olf said propellers inl a sense to aid the steering of said vessel, lost motion mechanism between said steeringV control mechanism and said pitch actuating means topermit a predetermined limited movement of said rudder from center position before said pitch actuating means begins to operate, and adjusting mechanism to adjust the amount of movement of said -lost motion mechanism.

`8. A steering system for vesselshaving a steering rudder and port and starboard variable pitch propellers, comprising pitch changing mechanisms connected respectively to change the pitch of each of said propellers, pitch actuating means for simultaneously actuating both of said pitch changing mechanisms in opposite sense to increase the pitch of one of said propellers and to decrease the pitch of the other of said propellers, steering control mechanism connected to actuate said rudder and said pitch-actuation means for automatically varying the pitch of said propel- 1ers in a sense to aid the steering of said vessel and mechanism to disconnect said rudder from said steering control mechanism to permit steering of said vessel solely by said propellers.

9. A steering system for vessels having Aa steering rudder and port and starboard variable pitch propellers, comprising pitch changing ""m'echanisms connected respectively to change the pitch of each of said propellerspitch actuating meansfor simultaneously actuating both off "said pitch changing mechanisms in opposite sense to increase the pitch of one of ysaid propellers and to decrease the pitch of the other of said propellers, steering control` mechanism connected to -actuate said rudder and said pitch- `actuation meansfor automatically varying the pitch of said propellers in a sense to aid the steer--` `ing of said vessel, and-means varying theratio o-f movement of said pitch actuating means to said rudder. JOHN HAYS HAMMOND, JR. 

